WO2019054702A1

WO2019054702A1 - Method and device for transmitting and receiving data in wireless communication system

Info

Publication number: WO2019054702A1
Application number: PCT/KR2018/010511
Authority: WO
Inventors: 김상범; 장재혁; 김성훈; 아기왈아닐; 진승리
Original assignee: 삼성전자 주식회사
Priority date: 2017-09-15
Filing date: 2018-09-07
Publication date: 2019-03-21
Also published as: US11778507B2; US20230089996A1

Abstract

Disclosed is a 5G or pre-5G communication system for supporting a data transmission rate higher than that of a 4G communication system such as long term evolution (LTE). Disclosed is a method by which a terminal transmits a buffer status report (BSR) in a communication system, comprising the steps of: allocating an uplink resource from a base station; comparing the number of padding bits with a value obtained by summing the size of the BSR and the size of a sub-header of the BSR; and transmitting, to the base station according to the comparison result, the BSR including information indicating the presence or absence of a field representing a buffer size for at least one logical channel group (LCG).

Description

Method and apparatus for transmitting and receiving data in a wireless communication system

Various embodiments of the present disclosure are directed to a method and apparatus for transmitting and receiving data in a wireless communication system, and more particularly, to a method and apparatus for transmitting and receiving control information for data transmission and reception in a wireless communication system.

Efforts have been made to develop an improved 5G (5 ^th -Generation) communication system or a pre-5G communication system to meet the increasing demand for wireless data traffic after commercialization of 4G (4 ^th -Generation) communication system . For this reason, a 5G communication system or a pre-5G communication system is called a system beyond a 4G network or a system after a LTE system (post LTE).

To achieve a high data rate, 5G communication systems are being considered for implementation in very high frequency (mmWave) bands (e.g., 60 gigahertz (60GHz) bands). In 5G communication system, beamforming, massive MIMO, and full-dimensional MIMO (FD-MIMO) are used to reduce propagation path loss and propagation distance of radio waves in a very high frequency band. , Array antennas, analog beam-forming, and large scale antenna technologies are being discussed.

In order to improve the network of the system, the 5G communication system has developed an advanced small cell, an advanced small cell, a cloud radio access network (cloud RAN), an ultra-dense network, (D2D), a wireless backhaul, a moving network, cooperative communication, coordinated multi-points (CoMP), and interference cancellation Is being developed.

In addition, in the 5G system, advanced coding modulation (ACM) schemes such as hybrid FSK and QAM modulation and sliding window superposition coding (SWSC), advanced connection technology such as FBMC (filter bank multi carrier), NOMA (non-orthogonal multiple access), and SCMA (sparse code multiple access) have been developed

In a cellular system, a connection setup with a network can be requested through a random access process. For example, random access can be performed in various situations, such as when the UE wishes to establish a radio link as an initial connection, to re-establish a radio link after a radio link failure, to form an uplink synchronization with a new cell in a handover .

Even if the UE performs the random access, the UE fails. At this time, the terminal retries the random access. In an environment in which a plurality of terminals perform wireless communication with a base station, appropriate control of retry of random access is requested.

In addition, the terminal operates a data buffer in wireless data transmission / reception with the base station. Effective management of data buffers can be related to data transmission and reception efficiency.

The present disclosure provides a method and apparatus for transmitting and receiving data in a wireless communication system for efficiently operating wireless data transmission and reception.

A terminal according to one embodiment of the present disclosure includes a processor for controlling the transceiver to receive backoff related information from the transceiver and the base station and for performing random access based on the received backoff related information .

A terminal according to another embodiment of the present disclosure may include a processor that transmits a preamble for a transceiver and system information to a base station and controls the transceiver to receive a random access response corresponding to the preamble.

A terminal according to another embodiment of the present disclosure includes a processor for transmitting information on a transceiver and buffer status and controlling the transceiver to receive uplink resource allocation information set based on information on the buffer status .

As described above, according to the present disclosure, the efficiency of random access can be greatly improved.

Also, as described above, according to the present disclosure, the buffer status of the terminal can be efficiently managed and transmitted / received.

1 illustrates a next generation mobile communication system according to an embodiment of the present disclosure.

2 is a flow diagram of a random access procedure in accordance with an embodiment of the present disclosure.

FIG. 3 illustrates a configuration of a random access response message according to an embodiment of the present disclosure.

FIG. 4 illustrates an E / T / R / R / BI MAC subheader according to an embodiment of the present disclosure.

5A illustrates a first format according to one embodiment of the present disclosure.

Figure 5B illustrates a second format according to one embodiment of the present disclosure.

Figure 5C illustrates a third format according to one embodiment of the present disclosure.

5D shows a PAR PDU according to one embodiment of the present disclosure.

6 is a flowchart for explaining operations of a terminal according to an embodiment of the present disclosure.

7 is a signaling flow diagram between a terminal and a base station according to an embodiment of the present disclosure;

8 shows a RAR PDU according to one embodiment of the present disclosure.

9 shows a RAR PDU according to another embodiment of the present disclosure.

10 is a flowchart for explaining the operation of a terminal according to another embodiment of the present disclosure.

11 illustrates an LTE system according to one embodiment of the present disclosure.

12 shows a wireless protocol architecture of an LTE system according to one embodiment of the present disclosure.

13 illustrates a message flow between a terminal and a base station in accordance with one embodiment of the present disclosure.

14A-14C illustrate a BSR format in accordance with one embodiment of the present disclosure.

15 is an operation flowchart of a terminal according to an embodiment of the present disclosure.

16 illustrates a message flow between a terminal and a base station according to another embodiment of the present disclosure.

17A and 17B illustrate a BSR format according to another embodiment of the present disclosure.

18 is a flowchart illustrating an operation of a terminal according to another embodiment of the present disclosure.

19 is a block diagram of a terminal according to an embodiment of the present disclosure;

20 is a block diagram of a base station in accordance with an embodiment of the present disclosure;

21 is a block diagram of a terminal according to an embodiment of the present disclosure;

22 is a block diagram of a base station in accordance with one embodiment of the present disclosure;

In the following description of the present disclosure, a detailed description of known functions and configurations incorporated herein will be omitted when it may obscure the subject matter of the present disclosure. Embodiments of the present disclosure will now be described with reference to the accompanying drawings.

A term used for identifying a connection node used in the following description, a term referring to network entities, a term referring to messages, a term indicating an interface between network objects, a term indicating various identification information Etc. are illustrated for convenience of explanation. Accordingly, the present disclosure is not limited to the following terms, and other terms referring to objects having equivalent technical meanings can be used.

For purposes of the following discussion, this disclosure uses terms and names defined in the 3GPP LTE (Long Term Evolution) standard, which is the most recent standard among existing communications standards. However, the present disclosure is not limited by the above terms and names, and may be equally applied to systems conforming to other standards. In particular, this disclosure is applicable to 3GPP NR (new radio: 5th generation mobile communication standard).

In various embodiments of the present invention, when an operation is described as being performed by a terminal, a base station or various entities, the same operation is performed in at least one processor, controller, transceiver, etc. included in the terminal, base station or various entities Can be read.

Referring to FIG. 1, the radio access network 10 may be configured as a next generation mobile communication system 10. The next generation mobile communication system 10 may include at least a new radio node B (hereinafter referred to as NR NB) 11 and a new radio core network (NR CN) 12. A new user equipment (NR UE or UE) 13 may be connected to an external network via the NR NB 11 and the NR CN 12. [

In one example, the NR NB 11 corresponds to an evolved node B (eNB) of the LTE system. The NR NB 11 may be connected to the NR UE 13 via a radio channel. The NR NB 11 can provide a higher level of service than the Node B.

In the next generation mobile communication system 10, most (or all) user traffic may be served through a shared channel. Therefore, in the next generation mobile communication system 10, an element (or a device) for collecting and scheduling state information such as a buffer state, an available transmission power state, and a channel state of UEs is required. This scheduling can be handled by the NR NB 11.

One NR NB 11 can generally control a plurality of cells. The next generation mobile communication system 10 can have an LTE maximum bandwidth or more in order to realize high-speed data transmission compared to LTE. Also, the next generation mobile communication system 10 can use orthogonal frequency division multiplexing (OFDM) as a radio access technology. Further, the next generation mobile communication system 10 can use a beam forming technique. The next generation mobile communication system 10 also includes an adaptive modulation and coding (AMC) scheme for determining a modulation scheme and a channel coding rate according to a channel state of the UE 13 Can be applied. The NR CN 12 can perform functions such as mobility support, bearer setup, and QoS setup. The NR CN 12 may be a device that performs various control functions as well as a mobility management function for a terminal. Also, the NR CN 12 may be connected to a plurality of base stations. In addition, the next generation mobile communication system 10 can also be interworked with the LTE system. Also, the NR CN 12 may be connected to the MME 14 via a network interface. The MME 14 may be connected to the eNB 15, which is an existing base station.

Random access can be performed when adjusting uplink synchronization or transmitting data. For example, the random access may be performed upon switching from the standby mode to the connection mode, RRC re-establishment, handover, and uplink data start. The terminal 21 can receive the dedicated preamble from the base station 22. In this case, the terminal 21 can transmit the preamble by applying the preamble. Otherwise, the terminal 21 can select one of two preamble groups and select a preamble belonging to the selected group. In this case, the selected preamble may be transmitted to the base station 22.

For example, it is assumed that the group includes group A and group B. If the channel quality state is better than a certain threshold value and the size of msg 3 is larger than a certain threshold value, the terminal 21 can select a preamble belonging to the group A. Otherwise, the terminal 21 selects a preamble belonging to the group B.

When the terminal 21 transmits the preamble in the n-th subframe (201), it can start a random access response (RAR) window from the (n + 3) th subframe. Also, the terminal 21 can monitor whether the RAR is transmitted within the window time interval (202). Here, the scheduling information of the RAR can be indicated by the RA-RNTI of the PDCCH. The random access-radio network temporary identifier (RA-RNTI) may be derived using the time used for transmitting the preamble and the radio resource position in the frequency axis. The RAR may include a BI, a RAPID, a timing advance command, an UL grant, and a temporary C-RNTI. A backoff indicator (BI) can be used for overload control of the corresponding cell.

For example, if the terminal 21 fails in random access, the terminal 21 may retry the random access after waiting for the backoff time derived from the BI value.

The BI value may be provided from the base station 22 or not. If the BI value is not provided, the terminal 21 can immediately retry the random access without the backoff time. If the RAR is successfully received in the RAR window, the MS 3 can be transmitted using the UL grant included in the RAR (203). Here, Msg3 may include other information depending on the purpose of random access. Table 1 below is an example of information included in msg 3 (hereinafter, Table 1 is an example of information included in msg3).

When RAR is received in the nth subframe, Msg3 may be transmitted in the (n + 6) th subframe. Here, HARQ can be applied from Msg3.

After the Msg3 transmission, the terminal 21 can start the timer. In this case, a contention resolution (CR) message may be monitored until the timer expires (204). In addition to the CR MAC CE, the CR message may include an RRC Connection Setup message or an RRC Connection Reestablishment message according to a random access purpose.

For example, in an LTE mobile communication system, a RAR includes one or more subheaders and one or more MAC RARs. Here, the RAR may include a MAC header 303 composed of one or more subheaders. In this case, the MAC header may be located at the beginning of the RAR.

Some of the subheaders may include the BI 301. In this case, there is no MAC RAR corresponding to the subheader. In addition, the corresponding one of the MAC RARs 304 may exist in the subheaders 302 including the ID of the preamble.

According to one embodiment of the present disclosure, the E field 401 may indicate whether another MAC subheader is present. In addition, the T field 402 may indicate whether the corresponding subheader includes a BI or whether the corresponding subheader includes a random access ID (RAPID). As an example, the R field 403 is a reserved bit. Also, the BI field 404 is used to derive the backoff time and may have a total of 4 bits in size. For example, in the case of LTE technology, one random access response message may include one subheader including a BI field.

For example, in the LTE technology, only one BI subheader can exist. Further, in the LTE technology, the same BI value can be applied irrespective of the random access of a certain condition or the random access in a specific event. As another example, the next generation mobile communication system 10 may apply different BI values in case of random access failure according to various conditions or events.

According to one embodiment of the present disclosure, the access category and the PREAMBLE_TRANSMISSION_COUNTER value may be considered as a specific condition or event.

For example, in LTE technology, ACDC, one of the barring mechanisms, can provide barring configuration information for each category corresponding to one application.

As another example, the next generation mobile communication system 10 proposes a category-based access control scheme similar to the existing ACDC. Here, a major difference between the category-based access control scheme and the existing ACDC is that the category is not limited to the application, but the other categories of the application, such as the service type, call type, terminal type, Signaling type, slice type, or a combination of these elements. That is, a category-based access control technique can control whether accesses belonging to other elements are granted access.

For example, the barring mechanism of the next generation mobile communication system 10 can be classified into two categories.

An example of one kind is the standardized access category. Here, the category is a category defined in the RAN level, that is, a category specified in the standard document. For example, a category corresponding to Emergency may be included in the standardized access category. All accesses may correspond to at least one of the standardized access categories.

Another example is a non-standardized access category. Here, the category is defined outside the 3GPP and is not specified in the standard document. In this respect, the category is the same as the category in the existing ACDC. For example, any access triggered in the terminal NAS (non-access stratum) may not map to a non-standardized access category.

For example, through NAS signaling or application level data transfer, the provider server can provide non-standardized category information to the terminal NAS. Here, the information may indicate which element such as an application corresponds to each non-standardized category. The base station can provide the terminal with the category list providing the barring setting information and the barring setting information information corresponding to each category using the system information. Also, the terminal AS can transmit the category list provided by the base station to the terminal NAS. The terminal NAS may map the triggered access to one of the categories according to a predetermined rule. In addition, the terminal NAS may transmit the mapped category to the terminal AS together with a service request. The terminal AS can determine whether access triggered by the terminal NAS is allowed (barring check) using the barring setting information.

According to one embodiment of the present disclosure, a base station may provide a BI value corresponding to one or more specific access categories. According to this, unlike in the existing LTE, the base station can provide one or more BI values to the UE. Here, the access category information corresponding to the BI may be instructed using a specific field of the system information or the BI subheader. In this case, the indication may be performed by a combination of the system information and the BI subheader.

The terminal can select the BI to be applied according to the access category corresponding to the access triggering the random access operation. This makes it possible to apply a differential backoff time for certain accesses. For example, for high-priority accesses, a short backoff time may be set relative to other accesses. If the BI corresponding to the access category is not provided from the base station, the general BI value can be applied.

If the UE does not receive the random access response message in the specific time window after the preamble is transmitted or if the ID of the preamble transmitted in the received random access response message is not included in the received random access response message, . In this case, the terminal can increment PREAMBLE_TRANSMISSION_COUNTER by one. When the counter value reaches preambleTransMax + 1, the UE can report a random access problem to an upper layer. Here, the preambleTransMax value can be signaled from the base station. For example, if the PREAMBLE_TRANSMISSION_COUNTER value is large, it may mean that the UE has failed random access several times.

According to one embodiment of the present disclosure, a BI value corresponding to PREAMBLE_TRANSMISSION_COUNTER may be provided. If the random access fails several times, it may mean that there is a lot of delay until the access succeeded. Therefore, it is necessary to provide a different BI value for the terminal that has failed the random access several times. For example, if the base station provides a BI value corresponding to a PREAMBLE_TRANSMISSION_COUNTER value of 3, the terminal may apply the provided BI value for a random access failure with a PREAMBLE_TRANSMISSION_COUNTER value of 3 or greater.

&Lt; Embodiment 1 >

According to the first embodiment, when providing one or more BI corresponding to various conditions or events, an additional field may be defined in the BI subheader of the MAC PDU for the purpose of indicating a plurality of BIs.

Specifically, FIG. 5A shows a first format 501 and a second format 502 including a BI field proposed in the first embodiment.

5A illustrates a first format that includes a BI field, in accordance with one embodiment of the present disclosure. Here, a 1-bit E-field 501-1 and a 1-bit T-field 501-2 may be the same as those of a field having the same name in LTE. For example, the E field indicates whether the next sub-header exists, and the T field can indicate whether the sub-header is a BI sub-header or a sub-header corresponding to a MAC RAR.

The first format 501 may include a field 501-3 including various conditions or event values after the E field and the T field. For example, an access category index value or a PREAMBLE_TRANSMISSION_COUNTER value can be inserted. In this case, the BI field 501-4 including the Backoff indicator corresponding to the condition or event value may be included after the field 501-3.

According to one embodiment of the present disclosure, the size of the field including the condition or event value 501-3 may be 2 bits, and the size of the BI field 501-4 may be 4 bits. According to another embodiment of the present disclosure, the field including the condition or event value 501-3 and the BI field 501-4 may be defined as respective values defined within a total of 6 bits. For example, the order of the fields including the condition or event value 501-3 and the BI field 501-4 may be changed.

For example, in the first format, a field 501-3 for indicating a condition or an event and a BI field 501-4 can not exceed a total of 6 bits. For example, if the size of the field 501-3 indicating the condition or the event is determined to be 2 bits, the total number of conditions or events that can be instructed is four. In an actual wireless environment, for example, such a condition may be exceeded.

Accordingly, a second format according to one embodiment of the present disclosure may allocate more bits to indicate a condition or event. For example, a subheader containing a BI field with 2 bytes is defined, of which 6 bits can be assigned to indicate a condition or event.

In addition, as in the first format, the E field 502-1 and the T field 502-2 may be the same as those of the field having the same name in LTE. For example, the first format may include a field 502-3 indicating a condition or an event after the E field 502-1 and the T field 502-2. In addition, the first format may include a BI field 502-4 including a Backoff indicator corresponding to the condition or event value.

According to one embodiment of the present disclosure, the size of the field 502-3 including the condition or event value may be set to 6 bits, and the size of the BI field 502-4 may be set to 8 bits. However, The field 502-3 and the BI field 502-4 may be defined as respective values defined within a total of 14 bits.

5C is a diagram for explaining a third format including a BI field proposed in the first embodiment. In addition, the order of the fields stored in the format may be changed.

According to one embodiment of the present disclosure, the first format and the second format may be suitable for indicating a condition or event belonging to a single category. In a real environment, conditions or events belonging to various categories may be considered.

Accordingly, a third format according to an embodiment of the present disclosure can be proposed. The third format may include an E field 503-1, a T field 503-2, a T2 field 503-3, an IND field 503-4, and a BI field 503-5. For example, the T2 field 503-3 indicates a specific category, the IND field 503-4 indicates a condition or an event, and the BI field 503-5 indicates a category or an event corresponding to the category indicated You can include a Backoff directive. For example, the T2 field may indicate the access category or PREAMBLE_TRANSMISSION_COUNTER, which is the category of the condition or event indicated in the IND field. Also, the IND field may include an access category index value or a PREAMBLE_TRANSMISSION_COUNTER value.

According to one embodiment of the present disclosure, the T2 field 503-3, IND field 503-4, and BI field 503-5 may be set to 2 bits, 4 bits, and 8 bits, respectively. The T2 field 503-3, the IND field 503-4, and the BI field 503-5 may be defined as different values within a total of 14 bits. In addition, the order of the T2 field 503-3, the IND field 503-4, and the BI field 503-5 may be random.

5D illustrates a PAR PDU, according to one embodiment of the present disclosure.

Specifically, FIG. 5D shows a RAR PDU comprising a plurality of BI subheaders, according to the first embodiment of the present disclosure.

According to one embodiment of the present disclosure, one RAR MAC header may include one or more BI subheaders. In one example, the first sub-header of the RAR PDU may be a common BI subheader 504-1. That is, when a BI subheader corresponding to a certain condition or event can not be applied, the common BI subheader 504-1 can be applied.

As an example, the common BI subheader 504-1 may be indicated via a T2 field. If there is a common BI subheader 504-1, the common BI subheader 504-1 is always located at the front of the MAC RAR header 504-2. If there are other BI subheaders 504-3, 504-4, and 504-5, the other BI subheaders may be located after the common BI subheader 504-1.

6 is a flowchart according to the first embodiment described above as an example.

Referring to FIG. 6, the terminal receives a RAR message including one or more subheaders from a base station (S610). In step S620, the UE determines whether the sub-header is a BI sub-header or an RAR sub-header based on the value of the T field of a specific sub-header. Through the value of the T2 field of the specific subheader, the terminal determines whether the subheader is a response subheader for a condition or an event (S630). The terminal determines whether the subheader is a response subheader for a condition or an event through the value of the IND field of the specific subheader (S640). The terminal stores the BI information (S650). If the random access fails, the terminal determines the backoff time by applying the BI corresponding to the condition or event related to the random access (S660). After waiting for the determined backkoff time, the terminal retries random access (S670).

&Lt; Embodiment 2 >

In the second embodiment of the present disclosure, a plurality of BI subheaders can be included in the header of the RAR PDU. In addition, the second embodiment of the present disclosure can provide, as system information, which condition or event each BI sub-header corresponds to.

For example, the BI subheader may include at least an E field and a BI field that were applied in LTE. In addition, the BI subheader can reuse the 1-byte format of LTE without modification. In addition, the BI subheader may be used to indicate specific information of a reserved bit of 2 bits of the existing format.

Instead of minimizing changes to the BI subheader format, the second embodiment of the present disclosure may include condition or event information as system information. Thus, the RRC signaling can be increased.

Here, the system information includes one list information. Each entry in the list can correspond to a single condition or event. Also, each entry can be mapped on a one-to-one basis with one BI subheader stored in the RAR MAC header. In addition, the entry storage order in the list can be matched with the storage order of the corresponding BI subheader in the RAR MAC header.

Referring to FIG. 7, the terminal 710 receives system information from the base station 720 (711). Here, the system information may include a condition corresponding to each BI subheader or setting information for an event. The order of the setting information for each BI subheader stored in the specific system information can be matched with the order of the BI subheader stored in the header of the RAR PDU.

Also, the terminal 710 can transmit the preamble to the base station 720 under a specific condition or an event (712). The base station 720 may send a RAR message to the terminal 710. Here, the RAR message may include one or more BI subheaders (713).

If the RAR message is not received within a specific time interval (RAR window) after transmission of the preamble, or if it fails to decode the RAPID corresponding to the preamble in the received RAR message, the terminal 720 issues a random access problem (714). The terminal 710 determines whether there is a corresponding one of the BI subheaders included in the received RAR message corresponding to the current condition and the event. The terminal 720 determines whether there is a corresponding current condition or event among the BI subheaders that have been stored. Here, if it exists, the terminal 720 can derive the backoff time by applying the BI value included in the BI sub header (715). If there is no corresponding specific BI subheader, the terminal 720 may apply a common BI subheader. If the backoff time expires, the terminal 720 may retry random access (716).

8 shows a RAR PDU according to one embodiment of the present disclosure.

Specifically, FIG. 8 shows a RAR PDU comprising a plurality of BI subheaders in a second embodiment of the present disclosure.

According to the second embodiment of the present disclosure, the header 801 of the RAR PDU may include a plurality of BI subheaders 801, 802, 803, 804, 805. Here, when there is a common BI subheader 801, the common BI subheader 801 may be disposed at the first position of the RAR PDU. Here, if it is not applied to any BI subheader corresponding to a condition or event related to the transmitted preamble, the terminal 710 can apply the BI value of (801) of the common BI subheader.

Configuration information about the presence or absence of the common BI subheader 801 and a condition or event corresponding to a plurality of BI subheaders may be provided as system information. Accordingly, the common BI subheader 801 and the BI subheader 801 corresponding to a specific condition or event can all have the same format. For example, the order of the setting information for each BI subheader stored in the system information may match the order of the BI subheader stored in the RAR header.

9 shows a RAR PDU according to another embodiment of the present disclosure.

Specifically, FIG. 9 is a second diagram illustrating a RAR PDU comprising a plurality of BI subheaders in a second embodiment of the present disclosure.

Referring to FIG. 9, specific information for distinguishing a condition or an event together with a condition or event information through system information may be included in a BI sub header. For example, the BI subheader according to an embodiment of the present disclosure may maintain the format of the 1-byte BI subheader of the LTE, but utilize the existing 2-bit reserved bits (T2 field of FIG. 9) .

Here, the specific information is information for distinguishing a condition or an event together with information provided as system information in the second embodiment. For example, the specific information can be used to indicate whether a particular BI subheader is a common BI subheader or a BI subheader belonging to a particular condition or category of events. As another example, the system information may provide the terminal 710 with information mapping a specific condition or event to one index value. In addition, the system information may include an index value in a specific field of the BI subheader. Accordingly, the corresponding BI subheader can be indicated to correspond to a specific condition or event. This is effective in reducing the amount of information stored in the system information. If there is a common BI subheader 901, the BI subheader 901 may be located at the first position of the RAR PDU. The order of the setting information for each BI subheader stored in the system information can be matched with the order of the BI subheader stored in the RAR header.

10 is a flowchart of a terminal according to the second embodiment described above as an example.

Referring to FIG. 10, the terminal 710 receives configuration information about each BI from the base station 720 (S1010). The terminal 710 receives a RAR message including one or more subheaders from the BS 720 (S1020). The terminal 710 determines whether the subheader is a BI subheader or an RAR subheader based on the value of the T field of a specific subheader (S 1030). The terminal 710 determines whether a subheader is a response subheader for a condition or an event based on the setting information or the value of the T2 field of the specific subheader (S1040). The terminal 710 stores the BI information (S1050). When the random access fails, the terminal 710 determines the backoff time by applying the BI corresponding to the random access-related condition or event (S1060). After waiting for the determined backkoff time, the terminal 710 retries random access (S1070).

&Lt; Example 3 >

According to one embodiment of the present disclosure, a base station can provide only a single BI subheader as in LTE technology. The random access associated with a condition or event provided by the BS as system information may ignore the BI subheader described above.

In this case, the condition or event may include SRB1 transmission, SI request, handover, and connection re-establishment. Here, disregarding the BI subheader may mean that the BI value included in the subheader may not be applied.

For example, random access unrelated to a condition or an event may re-attempt preamble transmission after waiting for a backoff time by applying the BI value of the BI subheader in case of random access failure. Here, the condition or event may be defined in advance or may be provided as system information. Whether or not to ignore the BI value according to a specific condition or event can be controlled by at least one indicator.

According to one embodiment of the present disclosure, the application of separate power ramping configuration information to specific conditions or events may be proposed.

For example, the power ramping setting information may be composed of powerRampingStep, preambleInitialReceivedTargetPower, and preambleTransMax values.

Here, powerRampingStep is a power ramping factor that is increased at the time of preamble retransmission, preambleInitialReceivedTargetPower is preamble initial transmission power, and preambletransMax is maximum preamble transmission power.

For example, the first power ramping configuration information may be applied to normal random access and the second power ramping configuration information may be applied to a specific condition or event. Here, the second power ramping setting information may include at least one of the above-described parameters. Also, the power ramping setting information may be controlled in conjunction with the backoff.

According to one embodiment of the present disclosure, methods of applying the BI value and the second power ramping configuration information may be proposed as follows.

- Option 1

A specific condition or event may be pre-defined (hard-coded) and provided to the terminal via system information. Also, the second power ramping setting information may be provided to the terminal as system information.

For example, if the triggered random access matches the specific condition or event, the BI value contained in the BI subheader of the random access response message (RAR) may be ignored. At the same time, the second power ramping setting information is applied, and the preamble transmission power can be calculated.

- Option 2

A specific condition or event may be provided to the terminal via the system information. Also, the second power ramping configuration information may be provided to the terminal through the system information.

As an example, if a specific condition or event is provided, the terminal may instruct the terminal to ignore the BI value and apply the second power ramping configuration information.

For example, if the specific condition or event information is provided as system information and the triggered random access is associated with the specific condition or event, the BI value contained in the BI subheader of the random access response message (RAR) may be ignored . Also, the second power ramping setting information may be applied to calculate the preamble transmission power.

- Option 3

In one example, the system information includes a first indicator, and the first indicator may be used to ignore the BI value and indicate whether to apply the second power ramping configuration information.

As another example, the first indicator may be delivered to the MAC CE rather than the system information. The first indicator may be represented by a one-bit field of a specific subheader including the BI field.

For example, if the first indicator is set and the triggered random access is associated with the specific condition or event, the BI value contained in the BI subheader of the random access response message (RAR) may be ignored. Also, the second power ramping setting information may be applied to calculate the preamble transmission power.

- Option 4

A specific condition or event may be pre-defined (hard-coded) and provided to the terminal via system information. Also, the second power ramping configuration information may be provided to the terminal through the system information.

For example, if the second power ramping configuration information is provided, the terminal may ignore the BI value and indicate whether to apply the second power ramping configuration information.

If the second power ramping configuration information is provided and the triggered random access is associated with the specific condition or event, the BI value contained in the BI subheader of the random access response message (RAR) may be ignored. Also, the second power ramping setting information may be applied to calculate the preamble transmission power.

- Option 5

In one example, the system information may include a first indicator, which indicates to ignore the BI value.

If the first indicator is set and the triggered random access corresponds to the specific condition or event, the BI value contained in the BI subheader of the random access response message (RAR) may be ignored.

For example, when the second power ramping setting information is provided, the second power ramping setting information may be applied to calculate the preamble transmission power.

- Option 6

Certain conditions or events can be pre-defined (hard-coded). Also, the second power ramping configuration information may be provided to the terminal through the system information.

If the triggered random access corresponds to the specific condition or event, the BI value included in the BI subheader of the random access response message (RAR) may be ignored.

When the second power ramping setting information is provided, the second power ramping setting information is applied, and the preamble transmission power can be calculated.

11 illustrates an LTE system in accordance with one embodiment of the present disclosure.

11, the LTE system (or wireless communication system) 30 includes a plurality of

base stations

31, 32, 33 and 34, a mobility management entity (MME) 35 and a serving gateway (S-GW) (36). A user equipment (UE) 37 accesses the external network via the

base stations

31, 32, 33, and 34 and the S-GW 36.

The

base stations

31, 32, 33, and 34 provide wireless connections to terminals (e.g., 37) that connect to the network as access nodes of the cellular network. That is, the

base stations

31, 32, 33, and 34 may collect status information such as the buffer status, the available transmission power status, and the channel status of the UEs in order to service the traffic of users. The

base stations

31, 32, 33, and 34 can support connections between the UEs and the core network (CN) through scheduling using the aggregated state information.

The MME 35 may be connected to a plurality of

base stations

31, 32, 33, and 34 as an apparatus for performing various control functions as well as mobility management functions for the terminal 37.

The S-GW 36 is a device that provides a data bearer.

The MME 35 and the S-GW 36 can further perform authentication and bearer management for the terminals connected to the network and can receive packets arriving from the

base stations

31, 32, 33 and 34 Or the packets to be transmitted to the

base stations

31, 32, 33, and 34. [

12, a wireless protocol of the LTE system is transmitted through a packet data convergence protocol (PDCP) 1211, 1218, a radio link control (RLC) 1212, 1217, a MAC medium access control (1213, 1216).

The

PDCPs

1211 and 1218 perform operations such as IP header compression / decompression, and the

RLCs

1212 and 1217 reconfigure PDCP packet data units (PDUs) to an appropriate size. The

MACs

1213 and 1216 are connected to a plurality of RLC layer devices configured in a terminal 1210, multiplex RLC PDUs into MAC PDUs, and demultiplex RLC PDUs from MAC PDUs.

The physical layers (PHY) 1214 and 1215 channel-code and modulate the upper layer data, transmit the data to a wireless channel by forming the OFDM symbols, demodulate and channel-decode the OFDM symbols received through the wireless channel, As shown in FIG. In addition, in the physical layer, HARQ (hybrid ARQ) is used for additional error correction. In the receiving end, transmission of the packet transmitted from the transmitting end is carried out with 1 bit. This is called HARQ ACK / NACK information.

The downlink HARQ ACK / NACK information for uplink transmission is transmitted through a physical hybrid ARQ indicator channel (PHICH) physical channel and the uplink HARQ ACK / NACK information for downlink transmission includes a physical uplink control channel (PUCCH) (physical uplink shared channel) physical channel.

Meanwhile, the PHY layer may be composed of one or a plurality of frequency / carriers, and a technique of simultaneously setting and using a plurality of frequencies in one base station 1250 is called a carrier aggregation (CA). CA technology refers to the fact that only one carrier is used for communication between a UE (user equipment, UE) 1210 and a base station (E-UTRAN NodeB, eNB) 1250, and that the main carrier and one or more subcarriers And further increases the amount of transmission by the number of subcarriers.

In LTE, a cell in a base station using a main carrier is referred to as PCell (primary cell), and a subcarrier is referred to as a secondary cell (SCell).

The technology in which the CA function is extended to two base stations is referred to as dual connectivity (hereinafter referred to as DC). DC technology, a UE connects and uses a master E-UTRAN Node B, a MeNB, or a Master Node B, and a secondary base station (secondary E-UTRAN Node B, a SeNB or a secondary Node B, SN) The cells belonging to the auxiliary base station are referred to as a master cell group (MCG), and the cells belonging to the auxiliary base station are referred to as a secondary cell group (SCG). The representative cell of the main cell group is referred to as a primary cell (hereinafter referred to as PCell), and the representative cell of the auxiliary cell group is referred to as a primary secondary cell (hereinafter referred to as PSCell) do. When using the above-mentioned NR, the MCG can use LTE technology and the SCG can be used as NR so that the UE can simultaneously use LTE and NR.

Although not shown in the figure, radio resource control (RRC) layers exist in the upper part of the PDCP layer of the UE 1210 and the base station 1250, respectively. You can send and receive configuration control messages. For example, the RRC layer may instruct the UE 1210 to measure neighboring cells, and the UE 1210 may report the measurement result to the BS 1250 using the RRC layer message .

13 illustrates a message flow between a UE 1310 and a BS 1320 in a method 1 of reporting a data buffer state for uplink data transmission according to an embodiment of the present disclosure.

Referring to FIG. 13, the terminal 1310 in the sleep mode (RRC_IDLE) performs connection to the base station 1350 for data transmission or for receiving a paging message indicating that there is data to be received from the network (1312).

In the sleep mode, data can not be transmitted because the terminal is not connected to the network in order to save power. Also, in the sleep mode, a transition to the connection mode (RRC_CONNECTED) is required for data transmission. When the terminal 1310 accesses the base station 1350, the terminal 1310 changes its state to the connection mode (RRC_CONNECTED).

The base station 1350 creates a logical (or virtual) channel through which data can be transmitted so that the terminal 1310 can transmit data. A logical (or virtual) channel through which data can be transmitted is called a data radio bearer (DRB).

In contrast, a logical (or virtual) channel over which a control signal can be transmitted is called a signaling radio bearer (SRB).

The DRB and the SRB each have a logical channel identity (LCID). When signaling or data is transmitted in the downlink or uplink, the DRB and the SRB transmit the logical channel identifier corresponding to the corresponding data type in the header in the MAC layer. Accordingly, the receiver can distinguish whether the packet is signaling or data. In addition, if the packet is a data packet, the receiving end can determine which DRB belongs and distinguish the received data.

The base station 1350 may transmit a RRCConnectionReconfiguration message to the UE to set up the DRB and may set a new DRB to the UE 1310. [ Here, the DRB setting information includes the above-described PDCP, RLC, and MAC layer related setting information (1312). For example, when a plurality of DRBs are set, separate setting information may be included for each DRB. In addition, logical channel group (LCG) information can be set for each DRB by MAC layer related information.

For example, when the base station 1350 sets up a total of 5 DRBs to the terminal 1310, the LCIDs may be assigned to the

DRBs

13, 14, 15, 6, and 7, respectively. In this case, the base station 1350 can group the

LCIDs

3 and 4, assign the

LCIDs

5 and 6 to the LCGs 1, and assign the

LCIDs

7 and 2 to the

LCGs

3 and 2, respectively.

For example, the LCG may be used by the terminal 1310 in requesting a resource to a base station 1350, which will be described later. For example, if the terminal 1310 has 100 bytes of data to be transmitted in LCID 3, 100 bytes of data to be transmitted in LCID 4, and 100 bytes of data to be transmitted in LCID 7, Instead of reporting the amount of data to be transmitted for each LCID, it can report to the base station 1350 that there is 200 bytes in LCG # 1 and 100 bytes in LCG # 3.

For the logical channel group, the BS 1350 can set the MS 1310 to transmit a short BSR, which will be described later, in case of any logical channel group. For example, assume that a scenario is set up to allow Short BSR to be transmitted for LCG # 1.

The terminal 1310 having received the setting information transmits an acknowledgment message to the base station 1350 indicating that the setting has been successfully received. To do this, a layer's RRCConnectionReconfigurationComplete message may be used (1313).

The terminal 1310 can report to the base station 1350 when the predetermined condition is satisfied with respect to the amount of data to be transmitted to each DRB in the buffer in the terminal 1310. This is called a buffer status report (BSR). Transmission of the buffer status report can be divided as follows according to the triggering condition.

- Type 1: regular BSR

o When the terminal has data that can be transmitted to the SRB / DRB belonging to the LCG, and the BSR retransmission timer (retxBSR-Timer) expires, the BSR

When the data to be transmitted from the upper layer (RLC or PDCP layer) is generated for the SRB / DRB belonging to the LCG and the data has higher priority than the logical channel / radio bearer belonging to any LCG, the transmitted BSR

o Data to be transmitted from an upper layer (RLC or PDCP layer) is generated for a logical channel / radio bearer belonging to the above LCG, and when there is no data in any LCG except for this data,

- Type 2: Periodic BSR

o The BSR transmitted when the periodic BSR timer (periodicBSR-Timer) set in the terminal has expired

- Type 3: Padding BSR

When the uplink resource is allocated and the padding bit that fills the remaining space for transmitting data is equal to or larger than the sum of the size of the BSR MAC CE and the size of the subheader of the BSR MAC CE,

If there are packets in the buffers of multiple LCGs, Truncated BSR is sent

Accordingly, when padding (i.e., remaining space) occurs when receiving the uplink resource allocation from the base station 1350, it is possible to send a long BSR or a short BSR / truncated BSR depending on the size of the remaining space. The long BSR format and the short BSR format are described in detail in FIG.

For example, when a regular BSR or a periodic BSR is triggered to be transmitted, if there is a packet only in the buffer of the LCG (for example, LCG # 1) permitted to transmit the short BSR among the set LCG of the terminal 1310 ), The UE 1310 generates and transmits a short BSR format BSR to the Node B 1350 (1315). The BS 1350 recognizes that there is data to be transmitted to the LCG # 1 of the corresponding MS, and allocates the uplink resources so that the data can be transmitted (1316). The UE 1310 receives the uplink resource allocation information and transmits data in the buffer to the corresponding resource (1317).

If a regular BSR or a periodic BSR is triggered to be transmitted, it is possible to transmit a short BSR to another LCG (for example, LCG # 2) other than the LCG (for example, LCG # 1) If there is a packet only in the buffer 1318, the terminal 1310 generates and transmits a BSR of the long BSR format to the base station 1350 (1319) even though there is data to be transmitted to only one LCG. The BS 1350 recognizes that there is data to be transmitted to the LCG # 2 of the MS 1310 and allocates uplink resources to the MS 1320 in order to transmit the data. The UE 1310 receives the uplink resource allocation information and transmits data in the buffer to the corresponding resource (1321).

When a regular BSR or periodic BSR is triggered to be transmitted and a packet exists in a buffer of a plurality of LCGs among the set LCGs of the UE 1310, the UE 1310 transmits a long BSR format And transmits the generated BSR to the BS (1323). In step 1324, the BS 1350 recognizes that there is data to be transmitted for each LCG of the corresponding MS and allocates UL resources to transmit the data. The UE 1310 receives the uplink resource allocation information and transmits data in the buffer to the corresponding resource (1325).

14A-14C are exemplary BSR format diagrams for buffer status reporting method 1 in accordance with an embodiment of the present disclosure.

Figures 14A and 14B illustrate the short BSR format described above in accordance with one embodiment of the present disclosure, and Figure 14C is an exemplary diagram of a long BSR format according to one embodiment of the present disclosure.

14A to 14C exemplify the case where the size of the buffer size (BS) field used by the short BSR format and the long BSR format is the same (for example, 7 bits).

Accordingly, as described above with reference to FIG. 13, when the short BSR format is set to be used for a specific LCG through the RRC message, the data can be transmitted using the short BSR format when there is data only in the corresponding LCG.

14A shows a case where a BS size is 7 bits and a size of 1 byte including an extra reserved bit (R bit) 141. FIG.

FIG. 14B shows a case where the BS size is 7 bits in the same manner. FIG. 14B includes information that can indicate which LCG ID the remaining one bit refers to. For example, assume that there are up to eight LCG identifiers in the NR, and for the two LCGs among them, a scenario is indicated in which the base station can use the short BSR format. Accordingly, if the BS 1350 is set to use the Short BSR for the two LCGs, when reporting BS information of the lower LCG identifier among the two LCG identifiers, the LCGID (143) bit is set to 0, When reporting the BS information of the highest LCG identifier among the 20 LCG identifiers, the LCGID 143 bit may be set to 1 so that the BS 1350 can report the buffer status for the corresponding LCG.

14C shows a long BSR format in which the amount of data of the buffer can be variably reported for each LCG identifier.

Referring to FIG. 14C, each of the 8 bits of the first byte may indicate an LCG (i.e., a bitmap). For example, each bit may indicate the presence or absence of BS fields 0 through 7 in each LCG. For example, if the corresponding bit is set to '1' according to the bit information of the bitmap, the buffer size information corresponding to the corresponding LCG or LCID is included.

For example, when there is data in the buffer in the LCG IDs # 1, # 5, and # 6, the bitmap is included as 01000110, and the buffer size corresponding to 1 in the bitmap is included. Fig. 14C shows a case where each buffer size has a length of 1 byte. In this case, a buffer status report of a total of 4 bytes is generated by combining the size of 1 * 3 = 3 bytes, which is the product of one bitmap bitmap, one bitmap bitmap and each buffer size. In this case, if the BS size is set to 7 bits, 2 ^ 7 = 128 levels of detailed buffer status can be reported, and byte order can be matched as shown in FIG. 14C.

The short BSR format can also be used for truncated BSR transmissions sent when the padding BSR is triggered. For example, if the terminal 1310 has data for a plurality of LCGs in the buffer, if the size of the padding bits is small enough to accommodate long BSRs capable of reporting all BSs for a plurality of LCGs, And transmits the truncated BSR. The short BSR and the truncated BSR can be distinguished through other LCIDs in the subheader of the MAC layer transmitted together when sending the corresponding BSR. Accordingly, the trunked BSR having the short BSR format can be transmitted, even though there is no data to be transmitted to the LCG having the short BSR, and the size of the BS can be zero.

Specifically, FIG. 15 shows an operation flowchart of the UE when the data buffer status reporting method 1 is used.

In FIG. 15, the terminal 1310 completes the connection procedure to the base station 1330 and assumes a state in the connection state (RRC_CONNECTED) (S1510). In addition, the UE 1310 receives the RRCConnectionReconfiguration message from the Node B 1330 and transmits an RRCConnectionReconfigurationComplete message as a confirmation message to the UE 1310 (S1520). From the RRCConnectionReconfiguration message, the terminal 1310 receives the DRB. The DRB setting information may include the above-described PDCP, RLC, and MAC layer related setting information. For example, when a plurality of DRBs are set, separate setting information is included for each DRB. In addition, the MAC layer related information can set information on which LCG belongs to each DRB. In addition, it can be set that a short BSR transmission is allowed for a specific LCG through a message of the RRC layer.

The terminal 1310 reports to the base station 1330 when the predetermined amount of data to be transmitted to each DRB is satisfied in the buffer in the terminal. This is called a BSR. Transmission of the buffer status report is divided as follows according to the triggering condition.

- Type 1: Regular BSR

o When there is data that can be transmitted to the SRB / DRB belonging to the LCG, the terminal 1310 transmits the BSR (retransmitted) when the BSR retransmission timer (retxBSR-Timer)

- Type 2: Periodic BSR

o Terminal 1310 receives a periodic BSR timer (periodic BSR-Timer)

- Type 3: Padding BSR

If there are packets in the buffers of multiple LCGs, Truncated BSR is sent

Accordingly, when padding (i.e., remaining space) occurs when receiving the uplink resource allocation from the BS 1330, the MS 1310 transmits a long BSR or a short BSR / truncated BSR according to the size of the remaining space. .

If a regular BSR or periodic BSR is triggered to be transmitted (S1530), data of a plurality of LCGs in the buffer of the LCG of the terminal 1310 is stored in the buffer, or only the buffer of one LCG in which transmission of the short BSR is not allowed (S1540-YES), the terminal 1310 generates and transmits the BSR of the long BSR format to the base station 1330 (S1551). If there is no data to be reported to the terminal 1310 or if there is a packet only in the buffer of one LCG permitted to transmit the short BSR (NO at S1540), the terminal 1310 generates a BSR of short BSR format, (S1552). Accordingly, the UE 1310 receives the uplink resource allocation from the Node B 1330 and transmits the uplink data to the corresponding resource (S1560).

Specifically, FIG. 16 illustrates a message flow between a terminal 1600 and a base station 1650 in a method 2 that reports a data buffer state for uplink data transmission according to an embodiment of the present disclosure.

16, the terminal 1600 in the idle mode (RRC_IDLE) is connected to the base station 1650 for the reason of generating data to be transmitted or receiving a paging message indicating that there is data to be received from the network (1601).

In the sleep mode, data can not be transmitted because the terminal 1600 is not connected to the network for power saving or the like, and a transition to a connected mode (RRC_CONNECTED) is required for data transmission. If the terminal 1600 succeeds in the connection procedure to the base station 1650, the terminal 1600 changes its state to the connection mode (RRC_CONNECTED).

The base station 1650 transmits a RRCConnectionReconfiguration message to the terminal 1600 to set a new DRB to the terminal 1600 in order to set a DRB (data radio bearer) . In this case, the setting information includes the above-described PDCP, RLC, and MAC layer-related setting information (1602).

When a plurality of DRBs are set, separate setting information may be included for each DRB. Also, information related to MAC layer can be used to set logical channel group (LCG) information for each DRB. For example, when the base station 1650 sets up a total of 5 DRBs for the terminal 1600, the logical channel identity (LCID) is set to 3, 4, 5, 6, 7, And so on. For example, LCIDs 3 and 4 can be combined to assign LCG 1,

LCID

5 and 6 to LCG 2, and LCID 7 to LCG 3.

The LCG is used when the terminal 1600 requests the base station 1650 to be described later. For example, if the terminal 1600 has 100 bytes of data to be transmitted at LCID 3, 100 bytes of data to be transmitted at LCID 4, and 100 bytes of data to be transmitted at LCID 7, Instead of reporting the amount of data to be transmitted for each LCID, it is possible to report to the base station 1650 that there is 200 bytes in LCG # 1 and 100 bytes in LCG # 3.

The terminal 1600 that has received the setup information may transmit a confirmation message to the base station 1650 indicating that the setup has been successfully received. The confirmation message can be transmitted using the RRConnectionReconfigurationComplete message of the RRC layer (1603).

The terminal 1600 reports to the base station 1650 when the predetermined amount of data to be transmitted to each DRB is satisfied in the buffer in the terminal. This is called a Buffer Status Report (BSR). Transmission of the buffer status report is divided as follows according to the triggering condition.

- Type 1: Regular BSR

o When the terminal 1600 has data that can be transmitted to the SRB / DRB belonging to the LCG, the BSR transmitted when the BSR retransmission timer (retxBSR-Timer) expires

- Type 2: Periodic BSR

o A BSR transmitted when the periodic BSR timer (periodicBSR-Timer) set to the terminal 1600 has expired

- Type 3: Padding BSR

If there are packets in the buffers of multiple LCGs, Truncated BSR is sent

Accordingly, when padding (i.e., remaining space) occurs when receiving the uplink resource allocation from the BS 1650, a long BSR / (long) truncated BSR is sent according to the size of padding (remaining space) short BSR / (short) truncated BSR. The long BSR format and the short BSR format are described in detail in Figs. 17A and 17B.

(1604) if the data to be transmitted is not in the buffer, or if there is data only in one LCG and the amount of the data is less than or equal to a predetermined threshold, the terminal (1600) (BSR) of the short BSR format to the base station 1650 and transmits it to the base station 1650 (1605). The base station 1650 recognizes that there is some data to be transmitted to any LCG of the corresponding terminal 1600, and allocates uplink resources so that it can transmit it (1606). The terminal 1600 receives information for uplink resource allocation and transmits data in the buffer to the corresponding resource (1607).

regular BSR or periodic BSR is triggered to be transmitted, if there is data in only one LCG and the amount of data is greater than a predetermined threshold 1608, then the terminal 1600 can not transmit data to only one LCG, (BSR) of the long BSR format to the base station 1650 (1609). The base station 1650 recognizes that there is data to be transmitted to any LCG of the corresponding terminal 1600, and allocates uplink resources to transmit the data in step 1610. The terminal 1600 receives information for uplink resource allocation and transmits data in the buffer to the resource 1611.

When a regular BSR or periodic BSR is triggered to be transmitted and a packet exists in a buffer of a plurality of LCGs among the set LCGs of the terminal 1600, the terminal 1600 transmits a long BSR format And transmits the generated BSR to the base station 1650 (1613). The base station 1650 recognizes that there is data to be transmitted for each LCG of the corresponding terminal 1600, and allocates uplink resources to transmit the data in step 1614. The terminal 1600 receives the uplink resource allocation information and transmits the data in the buffer to the corresponding resource (1615).

Specifically, FIGS. 17A and 17B are exemplary BSR format diagrams for buffer status reporting method 2.

17A is an exemplary diagram of the short BSR format described above, and FIG. 17B is an exemplary diagram of a long BSR format. 17A and 17B show examples in which the size of the buffer size (BS) field used by the short BSR format and the long BSR format is different (in FIGS. 17A and 17B, the BS field of the short BSR is 5 bits long, BS field is 7 bits).

Accordingly, as described above with reference to FIG. 16, if there is no BS value to be reported or if there is a BS value to be reported below a predetermined threshold value (threshold value) in only one LCG, it can be transmitted using the short BSR format.

17A shows an example of a 1-byte size including a logical channel group identity (LCGID) field 1701 indicating which LCG is BS information, and a BS field 1702 for transmitting the BS size of the LCG FIG. In this example, the size of the BS field is 5 bits, and information of 32 stages can be informed accordingly.

When the long BSR transmits data in the 7-bit BS field, only 128 steps are required. In contrast, when the 32-step information is transmitted, the amount of information to be transmitted may vary. Accordingly, one of the following methods can be used as a method of sending a 5-bit BS.

- Method 1: only the top 32 of the total 128 BS values for the 7-bit BS field

- Method 2: Use only the upper 32 odd index or even index, or a multiple (or modular 0) index of 4 (= 128/32) among the total 128 BS values for 7 bit BS field.

Method 3: Define separate BS values for 5-bit buffer size (BS) fields

Method 4: A total of 128 BS values for the 7-bit BS field are divided into 4 LCIDs, and the 0-31, 32-63, 64-95, and 96-127 indexes are respectively signaled

- Method 5: 7-bit signaling (i.e., 2-bit R-bit + 5-bit BS field) by further utilizing an extra reserved field in the MAC subheader when sending a short BSR.

The following Tables 2 and 3 are examples shown for explaining the

methods

1 and 2 described above.

When the above method 1 is used, the terminal uses only the values from Index 0 to 31. Accordingly, when the terminal uses the short BSR, it can report only up to 218 bytes, and the predetermined threshold described in FIG. 16 can be 218 bytes.

In the case of using the upper 32 even indexes in the above method 2, the predetermined threshold described in FIG. 16 is 4720 bytes. When the upper 32 odd indexes are used, the predetermined threshold described in FIG. 16 is 5212 bytes (Table 2 below is an example of information included in msg3)

(The contents of Table 2 are continued from Table 3.)

In the case of FIG. 17B, as in FIG. 14C, it is an example of a long BSR format in which the amount of data of the buffer can be variably reported for each LCG identifier. In this example, the 8 bits of the first byte can each indicate an LCG (i.e., a bitmap). For example, each bit may indicate the presence or absence of BS fields 0 to 7 in each LCG.

For example, when the corresponding bit is set to '1' according to the bit information of the bitmap, buffer size information corresponding to the logical channel group (LCG) or logical channel identity (LCID) is included. For example, when there is data in the buffer in the LCG IDs # 1, # 5, and # 6, the bitmap is included as 01000110, and the buffer size corresponding to 1 in the bitmap is included.

Referring to FIG. 17B, when a buffer has a length of 1 byte for each buffer size, a total of 4 bytes, that is, 1 byte of the bitmap, 1 number of 1s of the bitmap, and 1 * 3 = A buffer status report is generated.

Referring to FIG. 17B, when the BS size is 7 bits, 2 ^ 7 = 128 units of buffer status can be reported in detail. As shown in FIG.

The short buffer status report (BSR) format can also be used for truncated BSR transmissions sent when the padding BSR is triggered. For example, if the terminal 1600 has data for a plurality of LCGs in the buffer, if the size of the padding bits is small enough to include a long BSR capable of reporting all BSs for a plurality of LCGs, (E.g., short truncated BSR). In addition, a truncated BSR (long truncated BSR) with a long BSR format may be transmitted if the size of the padding bits can contain a part of the long BSR.

For example, three LCGs among eight logical channel groups (LCGs) have data to report, and a total of five bytes are required to send a long BSR format, including a MAC subheader having a size of 1 byte. For example, if there are four bytes of padding, the terminal 1600 may select and send only two of the three BS information using the long BSR format. (Eg long truncated BSR)

In this case, the terminal 1600 sets priorities based on the priority of each LCG or the highest priority among the priorities of the LCIDs contained in the LCG, and stores a number of pieces of BS information according to the padding size Can be determined.

18 is a flowchart of the operation of the terminal 1600 when the data buffer status reporting method 2 is used.

18, the terminal 1600 completes the connection procedure to the base station 1650 and assumes a state of being in a connected state (RRC_CONNECTED) (S1810). The terminal 1600 receives the RRCConnectionReconfiguration message from the base station 1650, The RRCConnectionReconfigurationComplete message is transmitted with the confirmation message (S1820).

From the RRCConnectionReconfiguration message, the UE 1600 is set up with a DRB, and the DRB configuration information includes the above-described PDCP, RLC, and MAC layer related configuration information. When a plurality of DRBs are set, separate setting information is included for each DRB. In addition, the MAC layer related information can set information on which LCG belongs to each DRB.

The terminal 1600 reports to the base station when the predetermined amount of data to be transmitted to each DRB is satisfied in the buffer in the terminal. This is called a BSR. Transmission of the buffer status report is divided as follows according to the triggering condition.

- Type 1: Regular BSR

- Type 2: Periodic BSR

- Type 3: Padding BSR

If there are packets in the buffers of multiple LCGs, Truncated BSR is sent

Accordingly, when padding (i.e., remaining space) occurs when receiving the uplink resource allocation from the BS 1650, a long BSR / truncated BSR is transmitted or a short BSR / truncated BSR is transmitted according to the size of the remaining space .

If the regular BSR or the periodic BSR is triggered to be transmitted (S1830), there is no data to be reported in the LCG set in the terminal 1600 or a packet having a predetermined threshold value or less exists in only one buffer of the LCG (S1840-Y), the terminal 1600 generates a BSR of the shot BSR format to the base station 1650 and transmits the BSR to the base station 1650 (S1851). When there are data to be reported to a plurality of LCGs among the set LCGs of the terminal 1600, or if there is a packet exceeding a predetermined threshold value only in the buffer of one LCG (S1840-N), the terminal 1600 BSR of the long BSR format and transmits it to the base station 1650 (S1852). Accordingly, the terminal 1600 receives the uplink resource allocation from the base station 1650 and transmits uplink data to the corresponding resource (S1860).

19, the terminal 1900 includes a radio frequency (RF) processor 1901, a baseband processor 1902, a storage 1903, a controller 1904 (or at least one processor) do.

The RF processor 1902 performs a function of transmitting and receiving a signal through a wireless channel such as band conversion and amplification of a signal. For example, the RF processor 1901 up-converts the baseband signal provided from the baseband processor 1902 to an RF band signal and transmits the RF band signal through an antenna. The RF processor 1901 down-converts the RF band signal received through the antenna to a baseband signal. For example, the RF processor 1901 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a digital to analog converter (DAC), an analog to digital converter .

Although only one antenna is shown in FIG. 19, the terminal 1900 may have a plurality of antennas. In addition, the RF processor 1901 may include a plurality of RF chains. Further, the RF processor 1901 may perform beamforming. For example, the RF processor 1m-10 may perform beamforming by adjusting the phase and size of signals transmitted and received through a plurality of antennas or antenna elements. In addition, the RF processor 1901 can perform MIMO and can receive multiple layers when performing a MIMO operation.

The baseband processor 1902 performs conversion between the baseband signal and the bitstream according to the physical layer specification of the system. For example, at the time of data transmission, the baseband processor 1902 generates complex symbols by encoding and modulating transmission bit streams. Also, upon receiving the data, the baseband processor 1902 demodulates and decodes the baseband signal provided from the RF processor 1m-10 to recover the received bitstream. For example, in accordance with an orthogonal frequency division multiplexing (OFDM) scheme, the baseband processor 1902 generates complex symbols by encoding and modulating transmission bit streams, and maps the complex symbols to subcarriers Then, OFDM symbols are constructed by performing inverse fast Fourier transform (IFFT) operation and cyclic prefix (CP) insertion. In addition, upon reception of data, the baseband processor 1902 divides the baseband signal provided from the RF processor 1901 into OFDM symbol units, and restores the signals mapped to the subcarriers through an FFT (fast Fourier transform) And then demodulates and decodes the received bit stream.

The baseband processing section 1902 and the RF processing section 1901 transmit and receive signals. Accordingly, the baseband processing section 1902 and the RF processing section 1901 can be referred to as a transmitting section, a receiving section, a transmitting / receiving section, or a communication section. Further, at least one of the baseband processor 1902 and the RF processor 1901 may include a plurality of communication modules to support a plurality of different radio access technologies.

Also, at least one of the baseband processing unit 1902 and the RF processing unit 1901 may include different communication modules for processing signals of different frequency bands. For example, different wireless access technologies may include a wireless LAN (e.g., IEEE 802.11), a cellular network (e.g., LTE), and the like. Also, different frequency bands may include a super high frequency (SHF) band (e.g., 2. NRHz, NRhz, 3G to 30 GHz), and a millimeter wave (e.g., 60 GHz) band.

The storage unit 1903 stores data such as a basic program, an application program, and setting information for operating the terminal 1900. In particular, the storage unit 1903 may store information related to a second access node that performs wireless communication using the second wireless access technology. The storage unit 1903 provides the stored data at the request of the control unit 1904. [

The control unit 1904 controls overall operations of the terminal 1900. For example, the control unit 1904 transmits and receives signals through the baseband processing unit 1902 and the RF processing unit 1901. The control unit 1904 also writes and reads data in the storage unit 1904. [ To this end, the control unit 1904 may include at least one processor. For example, the control unit 1904 may include a communication processor (CP) for performing communication control and an application processor (AP) for controlling a layer such as an application program. In addition, the control unit 1904 may include a multiple connection processing unit 1904-1.

Referring to FIG. 20, a base station 2000 includes an RF processor 2001, a baseband processor 2002, a backhaul communication unit 2003, a storage 2004, and a controller 2005.

The RF processor 2001 performs a function of transmitting and receiving a signal through a radio channel such as band conversion and amplification of a signal. For example, the RF processor 2001 up-converts the baseband signal provided from the baseband processor 2002 to an RF band signal and transmits the RF band signal through an antenna. Also, the RF processor 2001 downconverts the RF band signal received through the antenna to a baseband signal. For example, the RF processor 2001 may include a transmit filter, a receive filter, an amplifier, a mixer, an oscillator, a DAC, an ADC, and the like.

Although FIG. 20 shows only one antenna, the first access node may include a plurality of antennas. In addition, the RF processor 2001 may include a plurality of RF chains. Further, the RF processor 2001 may perform beamforming. The RF processor 2001 may perform beamforming by adjusting the phase and size of signals transmitted and received through a plurality of antennas or antenna elements. The RF processor 2001 may perform downlink MIMO operation by transmitting one or more layers.

The baseband processor 2002 performs a function of converting a baseband signal and a bit string according to a physical layer standard of the first wireless access technology. For example, at the time of data transmission, the baseband processing section 2002 generates demodulation (complex) symbols by encoding and modulating transmission bit streams. In receiving the data, the baseband processor 2002 demodulates and decodes the baseband signal provided from the RF processor 2001 to recover the received bitstream.

For example, according to the OFDM scheme, when transmitting data, the baseband processor 2002 generates complex symbols by encoding and modulating transmission bit streams, maps the complex symbols to subcarriers, and then performs IFFT and CP And construct OFDM symbols through insertion. In receiving the data, the baseband processor 2002 divides the baseband signal provided from the RF processor 2001 into OFDM symbols, restores signals mapped to subcarriers through an FFT operation, and then demodulates and decodes To recover the received bit stream.

The baseband processing section 2002 and the RF processing section 2001 transmit and receive signals as described above. Accordingly, the baseband processing section 2002 and the RF processing section 2001 may be referred to as a transmitting section, a receiving section, a transmitting / receiving section, a communication section, or a wireless communication section.

The backhaul communication unit 2003 provides an interface for performing communication with other nodes in the network. That is, the backhaul communication unit 2003 can convert a bit stream transmitted from the main base station 2000 to another node, for example, a sub-base station, a core network, etc., into a physical signal. In addition, the backhaul communication unit 2003 converts physical signals received from other nodes into bit streams.

The storage unit 2004 stores data such as a basic program, an application program, and setting information for the operation of the main base station. In particular, the storage unit 2004 may store information on the bearers allocated to the connected terminals, measurement results reported from the connected terminals, and the like. Also, the storage unit 2004 may provide multiple connections to the terminal, or may store information serving as a criterion for determining whether to suspend the terminal. The storage unit 2004 provides stored data at the request of the control unit 2005 (or at least one processor).

The control unit 2005 controls the overall operations of the main base station 2000. For example, the control unit 2005 transmits and receives signals through the baseband processing unit 2002 and the RF processing unit 2001 or through the backhaul communication unit 2003. Further, the control unit 2005 records and reads data in the storage unit 2004. Fig. To this end, the control unit 2005 may include at least one processor.

According to the embodiment of the present disclosure, when the BSR transmission is triggered, the terminal 1900 receives the detailed configuration for each DRB from the base station 2000 and accordingly generates and transmits a BSR format to the BS according to the set information, Buffer status can be reported.

Referring to FIG. 21, a terminal 2100 includes a transceiver 2110 and a processor 2120.

The transceiver 2110 can transmit and receive data to and from the base station.

The processor 2120 controls the terminal 2100 as a whole. Processor 2120 may control transceiver 2110 to receive backoff related information from the base station and perform random access based on the received backoff related information. Processor 2120 may also send a preamble for system information to the base station and control the transceiver to receive a random access response corresponding to the preamble. The processor 2120 may also control the transceiver 2110 to transmit information about the buffer status and to receive the uplink resource allocation information set up based on the information on the buffer status from the base station.

22, the terminal 2200 includes a transceiver 2210 and a processor 2220.

The transceiver 2210 can transmit and receive data to and from the terminal.

The processor 2220 controls the base station 2200 as a whole. Processor 2220 may control transceiver 2210 to transmit back-off related information to the terminal. In this case, the terminal can perform random access based on backoff related information. Processor 2220 may also receive a preamble for system information from the terminal and control the transceiver to send a random access response corresponding to the preamble. In addition, the processor 2220 can receive information on the buffer status from the UE and control the transceiver 2210 to transmit the uplink resource allocation information based on the information on the buffer status.

Methods according to the claims of the present disclosure or the embodiments described in the specification may be implemented in hardware, software, or a combination of hardware and software.

When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. One or more programs stored on a computer-readable storage medium are configured for execution by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to perform the methods in accordance with the embodiments of the present disclosure or the claims of the present disclosure.

Such programs (software modules, software) may be stored in a computer readable medium such as a random access memory, a non-volatile memory including a flash memory, a ROM (Read Only Memory), an electrically erasable programmable ROM (EEPROM), a magnetic disc storage device, a compact disc-ROM (CD-ROM), a digital versatile disc (DVDs) An optical storage device, or a magnetic cassette. Or a combination of some or all of these. In addition, a plurality of constituent memories may be included.

In addition, the program may be transmitted through a communication network composed of a communication network such as the Internet, an Intranet, a LAN (Local Area Network), a WLAN (Wide LAN), or a SAN (Storage Area Network) And can be stored in an attachable storage device that can be accessed. Such a storage device may be connected to an apparatus performing an embodiment of the present disclosure via an external port. Further, a separate storage device on the communication network may be connected to an apparatus performing the embodiments of the present disclosure.

In the specific embodiments of the present disclosure described above, the elements included in the invention are expressed singular or plural in accordance with the specific embodiments shown. It should be understood, however, that the singular or plural representations are selected appropriately according to the situations presented for the convenience of description, and the present disclosure is not limited to the singular or plural constituent elements, And may be composed of a plurality of elements even if they are expressed.

While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Therefore, the scope of the present disclosure should not be limited to the embodiments described, but should be determined by the scope of the appended claims, as well as the appended claims.

Claims

A method for transmitting a buffer status report (BSR) in a communication system, the method comprising:

Receiving uplink resources from a base station;

Comparing the number of padding bits with a sum of the size of the BSR and the size of the subheader of the BSR; And

Transmitting, to the BS, the BSR including information indicating whether there is a field indicating a buffer size for at least one logical channel group (LCG) according to the comparison result;

&Lt; / RTI >
The method according to claim 1,

Wherein a field indicating the buffer size exists in the BSR if the information indicating whether a field indicating the buffer size exists indicates a predetermined value.
The method according to claim 1,

Wherein the information indicating whether a field indicating the buffer size exists indicates whether a field indicating the buffer size exists for each of the plurality of LCGs.
The method according to claim 1,

Transmitting a truncated BSR having a short BSR format or a truncated BSR having a long BSR format to the BS according to the number of padding bits when the plurality of LCGs include data;

&Lt; / RTI >
5. The method of claim 4,

Transmitting a cut BSR having the long BSR format to the BS when the number of the padding bits is equal to or larger than a sum of a size of a short BSR and a size of a subheader of the short BSR;

&Lt; / RTI >
The method according to claim 1,

Transmitting a short BSR including information indicating a buffer size to the BS;

&Lt; / RTI >
A method for receiving a buffer status report (BSR) in a communication system, the method comprising:

Allocating an uplink resource to a terminal; And

Whether there is a field indicating a buffer size for at least one logical channel group (LCG) according to a result of comparing the number of padding bits with a sum of the size of the BSR and the size of the subheader of the BSR Receiving from the terminal the BSR including information indicating the BSR;

&Lt; / RTI >
8. The method of claim 7,

Wherein a field indicating the buffer size exists in the BSR if the information indicating whether a field indicating the buffer size exists indicates a predetermined value.
8. The method of claim 7,

Wherein the information indicating whether a field indicating the buffer size exists indicates whether a field indicating the buffer size exists for each of the plurality of LCGs.
8. The method of claim 7,

Receiving a truncated BSR having a short BSR format or a truncated BSR having a long BSR format from the UE according to the number of padding bits when the plurality of LCGs includes data;

&Lt; / RTI >
11. The method of claim 10,

Receiving a truncated BSR having the long BSR format from the UE when the number of the padding bits is equal to or greater than a sum of a size of a short BSR and a size of a subheader of the short BSR;

&Lt; / RTI >
1. A terminal for transmitting a buffer status report (BSR) in a communication system, comprising:

A transceiver; And

An uplink resource is allocated from a base station,

Compares the number of padding bits with a sum of the size of the BSR and the size of the subheader of the BSR,

A processor for transmitting, to the BS, the BSR including information indicating whether there is a field indicating a buffer size for at least one logical channel group (LCG) according to the comparison result;

.
13. The method of claim 12,

Wherein the processor performs an operation according to any one of claims 2 to 6.
1. A base station for receiving a buffer status report (BSR) in a communication system, the base station comprising:

A transceiver; And

Assigns an uplink resource to the terminal,

Whether there is a field indicating a buffer size for at least one logical channel group (LCG) according to a result of comparing the number of padding bits with a sum of the size of the BSR and the size of the subheader of the BSR A processor for receiving the BSR from the terminal;

/ RTI >
15. The method of claim 14,

Wherein the processor is operative to perform an operation according to any one of claims 8-11.